The present invention relates generally to the field of portable communication units, and more particularly to an improved portable communication unit that operates based upon discrete allocable blocks of airtime.
With the advent of the cellular telephone communications systems, the portable communications industry has experienced tremendous growth. It is estimated that there are presently over 20 million Americans who own and operate a cellular telephone. In addition, there are several million Americans who have applied for service with a cellular telephone carrier, but have been denied service because of insufficient or a bad credit history. As a result, a significant segment of the potential market for the cellular telephone industry is excluded from receiving or even being considered for cellular telephone service.
The prior art discloses various techniques for operating a communication system base site to accept or deny a request for access from a communication unit. For example, U.S. Pat. No. 5,274,368 to Breeden et al., assigned to Motorola, Inc., discloses such a system where a communication base site processes predetermined identification codes to determine whether a particular request for access to the base site is authorized. U.S. Pat. No. 4,908,848 to Hanawa discloses another technique for operating the mobile communication system to restrict certain types of call operations. Again, the system proposed by Hanawa, like the Breeden et al. system, requires modification of the communication system base site to recognize particular unique codes associated with a request for service from a particular portable communication unit. The modifications suggested by such prior art systems, however, have not been widely nor consistently implemented.
Theft of portable communication service, particularly with respect to cellular telephone service, has been increasing at an alarming rate and now represents a major problem in the industry. In some cases, the portable communication service user is placed in an awkward position where hundreds or even thousands of dollars of unauthorized communication service has been charged to the account of the user. If the user is able to establish that such service was unauthorized, the portable communication service provider will lose the revenue for the service provided that was unauthorized. In addition to theft of service, theft of portable communication equipment has also been increasing. Portable communication equipment, which may not be recognized as stolen until significant unauthorized service has been used, is very costly to the user and the service provider.
The present invention addresses and overcomes the limitations of such prior art systems, by providing a unique portable communication unit that may be easily configured, for example by a dealer for such units, to provide portable communication service in discrete predetermined blocks of service time. A significant advance of the present invention over systems proposed by the prior art, is that the unique operational characteristics of the invention are implemented in the portable communication unit itself rather than the communication system base site. Thus, the unique features of the portable communication unit of the present invention operate independent of any communication system base site that it might communicate with. As a result, a portable communication unit in accordance with the present invention may, depending upon the configuration specified by the dealer, operate with all the functionality and versatility of a conventional portable communication unit, communicating with any number of different communication system base sites, depending upon the location of the portable communication unit.
Due to the limited amount of airtime available for the portable communication unit of the present invention at any particular time, the unit of the invention will not be desirable as a target for theft. For it is the substantial and virtually unlimited additional airtime that is the objective when a portable communication unit is stolen or used without authorization.
In addition to the foregoing advantages, the unique features of the present invention facilitate the creation of a new class of portable communication units, useful for a variety of unique and desirable service situations. For example, the portable communication unit of the present invention, which may operate for a predetermined yet limited period of time, is particularly suited to certain industries, such as for equipment repair or service personnel who are given a portable communication unit to facilitate communication during service calls. The limited amount of airtime is a feature that ensures that the unit is not used for significant periods of time when unauthorized. In addition, the portable communication unit of the present invention is also particularly well-suited for individuals with short term communications needs, such as on a rental basis, perhaps also in association with the rental of an automobile.
In accordance with one embodiment of the invention, when a user exhausts a block of airtime, the user may contact the dealer or manufacturer of the portable communication unit to obtain a code that may be entered to activate an additional block of airtime. Such codes are known to, or may be generated by the dealer, based upon several variables, some of which are unique to the particular portable communication unit. A dealer will, typically, require either a pre-payment or other assurance of payment before providing the user with a code to activate an additional block of airtime, particularly when the unit is used in the context of users who have special credit needs. When the correct code is input, an additional predetermined and discrete block of airtime is activated and may be used to operate the portable communication unit.